Control of follicular development during and after lactation in sows.

Follicular development during early lactation in the sow is characterized by a large population of small-sized follicles and a small population of medium-sized follicles. As lactation progresses there is a gradual shift in number of follicles into medium- or large-sized categories and the percentage of follicles classified as atretic declines. Weaning at birth often leads to aberrant follicular development, apparently because the positive feedback response of LH to oestradiol does not occur during the first week post partum.

Effect of health status on culling and reproductive performance of Holstein cows.

Data were from 492 cows that calved between October 1976 and May 1977 in eight Holstein herds in Michigan. Cows were classified as those without any health-related problems during lactation; those with minor reproductive health problems not serious enough to require veterinary treatment; and those with health problems severe enough to require veterinary treatment. Among primiparous cows 4.

Malignant lymphoma of the meninges in two dogs.

Two cases of malignant lymphoma of the leptomeninges in dogs are described. Both involved the subarachnoid space overlying the cerebrum and cerebellum and in one dog there was infiltration of neoplastic lymphocytes into the leptomeninges of the cervical spinal cord and nerve roots. These cases appeared to represent primary meningeal lymphoma, except that lymphoma was present in an ovary of one of the dogs and here the meningeal lymphocytes were demonstrated to be B cells by the peroxidase-antiperoxidase method for cytoplasmic immunoglobulin.

Hepatic and gastric amebiasis in black and white colobus monkeys.

Three cases of hepatic amebiasis and one case of gastric amebiasis were diagnosed in black and white colobus monkeys during a 9-month period. The diagnosis was difficult because of the absence of trophozoites and cysts in the feces and because of few trophozoites found in many of the hepatic lesions. Indirect hemagglutination titers were diagnostic in 2 monkeys.

Treatment of long-term anestrous sows with estradiol benzoate and GnRH: response of serum LH and occurrence of estrus.

Seventeen primiparous sows, anestrous for 41+/-4 days after weaning, received i.m. injections of 500 microg estradiol benzoate (EB) or corn oil.

Effects of methionine hydroxy analog on milk secretion and ruminal and blood variables of dairy cows fed a low fiber diet.

Twenty-eight Holstein cows were in a reversal trial to determine effects of adding 34 g/day of methionine hydroxy analog to a low fiber ration. Cows were subjected to this feeding treatment sequence after parturition: days 1 through 28, normal fiber ration; days 29 through 56, low fiber ration; days 57 through 77, low fiber ration with or without 34 g/day of methionine hydroxy analog; days 78 through 98, low fiber ration; days 99 through 119, low fiber ration with or without 34 g/day of methionine hydroxy analog (days 57 through 77 treatments reversed). Milk, rumen fluid, and blood were collected at regular intervals during each period.

Influence of the ovary on estradiol-induced luteinizing hormone release in postpartum milked and suckled Holstein cows.

Holstein cows were assigned at parturition to be milked (n = 10) or suckled by four calves each (n = 10). One-half of each group was ovariectomized bilaterally (ovex) at the end of wk 1 and the remaining one-half was ovariectomized unilaterally (intact) at the end of wk 2. Cows were challenged with 400 micrograms estradiol-17 beta (im) at the end of wk 1, 2, 3 and 4 (24 h after surgery) and blood was collected at 0, 12, 14, 16, 18, 20, 22, 24 and 26 h after estradiol to determine luteinizing hormone (LH) concentration.

Characterization of summer infertility of sows in large confinement units.

Data were from 3119 farrowings in three large swine confinement units in eastern North Carolina. Litters were weaned during April through October. Interval to first estrus after weaning was greater during June through September than during other months.

Reproductive traits of Holsteins and Jerseys. Effects of age, milk yield, and clinical abnormalities on involution of cervix and uterus, ovulation, estrous cycles, detection of estrus, conception rate, and days open.

Two hundred and twelve Holstein and Jersey cows were in a study to determine factors that affected reproductive traits. First ovulation occurred about 3 wk postpartum, and interval to first ovulation was greater in cows that had clinical abnormalities postpartum than in normal cows. Jerseys producing more milk ovulated sooner postpartum than lower producing herdmates.

Relationships among type of parturition, type of discharge from genital tract, involution of cervix, and subsequent reproductive performance in Holstein cows.

Data were from 492 Holstein cows calved between October, 1976, and May, 1977, in eight herds in Michigan. Diameter of the cervix of each cow was estimated by palpation at 8 to 21 days postpartum and again 2 wk later. Parturition and postpartum discharge from the genital tract were classified as normal or abnormal.

Influence of herd relocation upon production and endocrine traits of dairy cows.

Effects of potential stress encountered by two Holstein herds relocated into a new double-six herringbone parlor and free-stall facility were studied by evaluating alterations of milk yield and fat percentage, mastitis status, corticosteroids, and heat detection. One-half of one herd (18 cows) was moved 100 m to new facilities (Merged), and the remaining 18 cows were maintained in their original tie-stall barn (Control). The same day, the second herd of 50 cows (Moved) was transported via stock trailer 7 km to new facilities.

Effect of feeding fat and altering weaning schedule on rebreeding in primiparous sows.

Primiparous sows that farrowed on a commercial farm during late summer in 1980 (n = 65) or late winter in 1981 (n = 62) and lactated 3 to 4 wk were used. Sows were assigned in a factorial experiment to one of two lactation diets (control or 10% fat-supplemented) and one of three periods (0, 2 or 5 d) of early weaning of the heaviest one-half of the litter. Days from weaning to estrus averaged 16.

Pulsatile administration of gonadotropin releasing hormone to lactating sows: endocrine changes associated with induction of fertile estrus.

Two experiments were conducted to determine whether pulsatile administration of gonadotropin releasing hormone (GnRH) would induce estrus and ovulation in lactating, anestrous sows. In each experiment, six lactating sows received GnRH, i.v.

Effect of estradiol on hypothalamic GnRH and pituitary and serum LH and FSH in ovariectomized pigs.

Two experiments were conducted to measure pituitary gonadotropins, hypothalamic-gonadotropin releasing hormone (GnRH) and pituitary response to GnRH during periods when serum luteinizing hormone (LH) was suppressed by estradiol-17 beta (e2) in ovariectomized pigs. In the first experiment, 10 ovariectomized gilts were assigned to two groups of five each according to time of slaughter (24 or 36 h after injection). Within each group, gilts were given corn oil (n = 2) or 400 micrograms E2 (n = 3).

Effect of altering suckling intervals of early-weaned pigs on rebreeding performance of sows.

Sows on two commerical farms were assigned to have their pigs weaned after a 3-week lactation (control, n=160) or after a 3-week lactation that included a 48-hr period of interrupted nursing before weaning (altered-suckling, n=122). Sows in the altered-suckling groups were paired, and each member of a pair was separated from both litters during the alternate 12-hr periods. Thus during the final 48 hr before weaning, each sow in the altered-suckling group had two 12-hr periods when no litters were present and two 12-hr periods when two litters were present.

Effect of molybdate on androgen receptor levels in canine prostate.

A comparative study on the stabilizing effect of sodium molybdate on androgen receptors was performed using canine prostates. Prostates from intact male dogs of mixed breeds were run in parallel sucrose density gradient analyses, using buffer systems with or without molybdate. Prostates that were homogenized in a molybdate buffer showed a significant increase in androgen receptor content relative to those in a molybdate-free system.

Thymic dysfunction in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is, in the great majority of cases, a neoplastic proliferation of B cells. The associated immunologic dysfunction accounts for many of the clinically associated phenomenon such as infection and second malignancies. Much of this dysfunction has been attributed to poor B-cell function.